双基地海底散射建模与仿真分析

海底的声散射是产生浅海混响的主要原因之一。采用小斜率近似方法研究了粗糙液-液分界面的海底散射问题,通过一个统一的方法实现微扰近似和Kirchhoff近似的无缝衔接且不受表面高度均方根条件限制。类比APL-UW模型,利用最低阶小斜率近似求解粗糙海底界面散射截面,并结合Jackson等人的海底沉积层体积散射截面表达式,建立了一个计算双基地海底散射强度的＂小斜率-体积＂模型。针对几种典型的海底类型进行了数值仿真与性能分析,并将数值预报结果与APL-UW模型进行了对比。结果表明,小斜率-体积模型在整个角度范围内较为准确,并且与APL-UW模型的预报结果吻合程度较高,两者散射强度差值小于2 dB。

Modeling and simulation analysis of bistatic seafloor scattering

Scattering of sound due to seafloor sediment is the main source of shallow water reverberation.Seafloor scattering from the rough liquid-liquid interface is investigated by using the small-slope approximation（SSA）.The SSA employs a unified method that seamlessly connects the small-roughness perturbation approximation and Kirchhoff approximation without any restriction on the RMS height of surface.Analogous to well-known APL-UW model,a ＂SSA-Volume＂ model is provided for calculating the bistatic scattering strength,which combines roughness-scattering cross section predicted with the lowest-order SSA and volume-scattering cross section formulated by Jackson et al.Numerical simulation and performance analysis are conducted on several typical types of seafloor,and the predictions are compared with the APL-UW model.It is found that the SSA-Volume model is more accurate in the whole range of angle and the numerical results also show good agreement between the predictions of SSA-Volume model and APL-UW model,with slight differences of scattering strength less than 2 dB.